Teaching Grammar as a part of the lesson, in small fragments and then having some practise I feel is my way of doing grammar . However sometimes I do revisit a grammar point if I feel the students are struggling with understanding, and usage. I do agree with the author and have experienced the frustration when students continue to make the same mistakes even after having had instructions on how to use a particular tense or form, it is definitely a case of taking one step forward and two steps backward.
Teaching Grammar Mc Nuggets style is not exactly how I would say the process of grammar teaching is with my colleagues. It's mostly a PPP model, with a little warm up or introduction, using a text or discussion which is geared to lead to the grammar point. This followed by some expalnation, then may be answering any doubts or questions. Then some practise.With this methods I feel more in control, and at ease. But there are many times when I'm trying to teach a particular Grammar point, another one crops up, and I realise the follies of teaching grammar points in isolation.
I think it is the linearity and complexity of acquiring grammar that may be responsible for younger students making far more progress than older ones. This may be because of motivation, need or just a case of being able to adapt easily at a younger age. It is in the end a process of acquiring language with all it's different rules and variations.